1. Field of the Invention
This invention relates to a phenylenesulfide resin composition. More specifically, this invention relates to a resin composition comprising a poly-p-phenylenesulfide, a poly-m-phenylenesulfide and a p-phenylenesulfide/m-phenylenesulfide block copolymer.
2. Description of the Prior Art
Poly-p-phenylenesulfides (hereinafter referred to as P-PPS) and poly-m-phenylenesulfides (hereinafter referred to as P-MPS) are well-known polymers. Particularly, P-PPS are being used in various fields utilizing their excellent heat resistance, chemical resistance, processability, mechanical characteristics, flame retardance, and other desirable characteristics.
On the other hand, a P-MPS has a low glass transition point and does not readily crystallize from its molten state; it behaves as an amorphous polymer under ordinary molding conditions. A P-MPS has excellent melt flowability and, when blended with a P-PPS, it improves the melt flowability of the P-PPS.
A composition consisting of a P-PPS and a P-MPS has melt flowability superior to that of a P-PPS. The composition, however, has defects in that these two polymer components lack compatibility, and clouding appears in the resulting quenched sheets, oriented films (thermally untreated or crystallized by heat-treatment), or non-stretched filaments or stretched filaments produced from the composition. When dynamic viscoelasticity is measured with a crystallized sheet sample produced from a composition consisting of the P-PPS and P-MPS, it is found that the loss tangent (tan .delta.)-temperature curve becomes broad, and the respective tan .delta. values corresponding to the P-MPS and P-PPS tend to appear separately. From this, also, it can be said that the two components have insufficient compatibility in such compositions.